Examine source code of PressPixie

{
  "name": "PressPixie",
  "description": "PressPixie Extension",
  "version": "1.0",
  "manifest_version": 2,
  "icons": {
    "16": "images/16.png",
    "32": "images/32.png",
    "48": "images/48.png",
    "128": "images/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@presspixie.com"
    }
  },
  "browser_action": {
    "default_icon": {
      "16": "images/16.png",
      "32": "images/32.png",
      "48": "images/48.png",
      "128": "images/128.png"
    },
    "default_title": "PressPixie",
    "default_popup": "popup.html"
  }
}